Synthesis of new symmetrical cylindrical macrotricyclic ligands 1a,b, where two cyclam subunits are linked through nitrogen atoms by two aromatic chains of various lengths (meta-xylylenyl, para-xylylenyl) has been achieved. These compounds have been prepared according a five step procedure. The readily available trisheteroprotected cyclam 4 has been reacted with the appropriate bis(bromomethyl)benzene to give the bimacrocycle intermediates 5a,b. The selective deprotection of the tert-butyloxycarbonyl group leads to the diamine bimacrocycles 6a,b. Condensation of these diamines with the appropriate diacid dichloride under high-dilution conditions yields the diamide macrotricycles 7a,b in a significant yield. After reduction of the amide moieties and deprotection of the tosyl groups, new cylindrical macrotricycles la,b were obtained. Macrotricyclic ligands la, b coordinate Cu2+ and Ni2+ to form binuclear species. The crystal structure of the [Ni-2(1a)](ClO4)(4).2CH(3)CN complex has been determined by single-crystal X-ray analysis. C18H30N4Ni(ClO4)(2).CH3CN crystallizes in the triclinic space group P (1) over bar with unit cell dimensions of a = 10.716 (3) Angstrom, b = 12.805(4) Angstrom, c = 9.292(3) Angstrom, alpha = 95.82(2)degrees, beta = 103.06(2)degrees, gamma = 93.94(2)degrees, and V = 1227.8 Angstrom(3), Z = 2, 2396 observations, and R(F) = 0.036. The cationic part of the complex is a dimer lying on a crystallographic inversion center. Each metal ion is coordinated to four nitrogen atoms of a cyclam unit giving an approximatively square planar coordination geometry, with an intermetallic distance of 6.830(1) Angstrom. The ESR spectra of the binuclear Cu2+ complexes clearly show metal-metal cooperative interactions.